A few years back, I had plans to meet up with some friends in another city.

That is, until I discovered that a friend whod booked after me had paid less.

(Thus rendering you the smuggest of all.)

This new hotel rebooking service is its first expansion beyond that.

Heres how it works.

To use Service, you must first connect your Gmail or Hotmail account.

Once you do that, Service will continually scan your inbox for relevant metadata.

To do this, it only needs your name and confirmation number, which it grabbed from your email.

Itll continue this process until the booking becomes non-refundable, which is usually 24 to 48 hours before check-in.

So, if it saved you $30, Service will charge your credit card $9.

And thats only if you actually stay at the hotel.

For frequent travelers, theres also a subscription plan that costs $49 per year.

With that route, all the savings you earnwhether through airline delay compensation or hotel bookingsare yours to keep.

(Which is probablyhow you should book hotels anyway.)

Bookings must be refundable and changeable, and made with cashnot points.

They can be either domestic or international.

How Much Will You Actually Save?

Hotel prices arent nearly as volatile as plane tickets (orAmazon).

So is there really that much to gain from tracking them?

Hotel rates fluctuate all the time, said Service CEO Michael Schneider.

The likelihood theyre going to drop often depends on the market.

New York City, for example, usually starts high and drops as you get closer to check-in.

And San Francisco is the complete opposite: It starts low and goes high.

The average drop is 10 percent, and the average rate is $153 per night.

In other words, you might save around $15 per night on a typical booking.

But remember, he added, it could drop multiple times before you ever check in.

I, for one, am probably going to give Services hotel feature a shot.